Many types of roof ventilators for venting attic or rafter spaces are found in the prior art. Some are of the turbine type which are wind-driven. Evacuation of attic space area may also be accomplished by fans which are generally mounted on the roof and which may be thermostatically controlled to exhaust hot air.
Other types of roof ventilators are static venting devices mounted over the elongated opening along the roof ridge of a building. In most cases, these vents comprise a sheet metal structure having air passageways or perforations.
Representative of these type of ventilation devices are shown in U.S. Pat. No. 4,545,291 which discloses a ventilator comprised of sheet metal having the inner baffle and flue portions in an outer storm band casing. Louvers are provided in the base and baffle portions of the sidewall.
U.S. Pat. No. 3,949,657 shows a ventilated cap which may be placed over the opening in the ridge of the roof which has a pair of beveled edge vent parts. Each vent part has transversely oriented openings extending from one beveled edge to the other. These vent parts are placed side-edge to -side-edge over the opening in the roof ridge and secured to the underlying roof surfaces.
U.S. Pat. No. 4,558,637 discloses a ventilating member having a central inverted V-shaped portion connecting the sides. Louvers and shield portions are located adjacent to side louvers to prevent precipitation from passing through the support member and down into the ridge roof openings.
U.S. Pat. No. 4,573,291 discloses a ridge covering having flexible sealing strips arranged between the covering caps fastened to the ridge or hip board and the roofing tiles.
U.S. Pat. No. 4,325,290 shows a ridge ventilator for the roof of a building which includes porous, non-woven and fiberous filter media selectively installed in the ventilator to prevent infiltration of moisture through the ventilator into the space below the roof.
One roof vent system which has been commercially utilized is shown in U.S. Pat. No. 5,339,582 and sold under the designation “Cor-A-Vent.” This patent shows an air dam mounted on a vent having openings extending transversely. The air dam includes an outer and upper flange and a lower leg with the outer edge of the flange being spaced from the inner surface of a covering over the roof ridge to insure proper air flow from the roof peak and to form a barrier against the ingress of wind-driven moisture into the vent openings.
My prior patent, U.S. Pat. No. 6,128,870, discloses a roof vent system having sidewalls which are secured in spaced-apart relationship by flashing sections to the roof ridge. Spacers are provided at spaced-apart locations along the sidewalls. The spacers may be extruded, square tubular sections, Z-section or other configurations. A screen extends between the sidewalls. A roof cap has a web which is held in place between the fasteners. The roof cap has flanges at its upper end which support a roof member such as a tile in an elevated position above the ridge to provide sufficient venting.
The requirements for ventilation of attics and rafter spaces set forth various building codes such as the International Residential Code. Generally, these codes prescribe a minimum total net-free ventilating area which generally is established to not be less than 1/150th of the area of the space ventilated except that the total area is permitted to be reduced to 1/300 providing at least 50%, and not more than 80%, of the required ventilating area is provided by the ventilators located in the upper portion of the space. The net free cross ventilation area may also be reduced when a vapor barrier having a transmission rate not exceeding an established rate is installed on the warm side of the ceiling.
While systems such as that shown in my prior patent have experienced commercial success, there nevertheless exists a need for a simple, easy to install roof vent system which will comply with building codes and which is adaptable to various installation applications.